Dropout fuse cutout



June 23. 1964 A. J. FINK ETAL DROPOUT FUSE CUTOUT 3 Sheets-Sheet 1 FiledFeb. 23, 1961 June 23, 1964 A. J. FlNK ETAL 3,138,681

DROPOUT FUSE CUTOUT Filed Feb. 23, 1961 3 Sheets-Sheet 5 Fi .I4 26F|g5l2 28 27 9 Fig. l3 F 24 H M l L Fig. l6 q- 1,2 as 34 as Fig. I? [aq- Q Fig. 20

United States Patent 3,138,681 DROPOUT FUSE CUTOUT Austin J. Fink andRobert F. Shelton, Bloomington, Ind., assignors to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of Pennsylvania FiledFeb. 23, 1961, Ser. No. 91,219 Claims. (Cl. 200-114) This inventionrelates, in general, to electric circuit interrupters, and, morespecifically, to dropout fuse cutouts.

This invention is an improvement over the dropout fuse cutout disclosedand claimed in copending application Serial No. 848,596, filed October26, 1959, by Austin I. Fink, and assigned to the assignee of the presentapplication.

It is an object of this invention to increase the interrupter rating ofthe dropout fuse cutout in the hereinbefore mentioned copendingapplication.

More specifically, it is an object of this invention to increase therating of the fuse cutout of the copending application by improving theoperating mechanism and contact assembly mechanism.

Still more specifically, it is an object of this invention to increasethe rating of the fuse cutout of the copending application by increasingthe bursting strength of the fuse holder, by strengthening portions ofthe operating mechanism to withstand greater reaction due to jet forceson the operating mechanism during circuit interruption, and by utilizingcontacts maintaining contact more firmly to resist possible burning ofthe contact surfaces and to provide relative movement between partsduring interruption without overstressing the stationary contacts.

Further objects and advantages will readily become apparent to thoseskilled in the art upon reading the following specification, taken inconjunction with the drawings, in which:

FIG. 1 illustrates a generally vertical sectional view taken through theenclosed fuse cutout of the present invention, the fuse holder doorbeing shown in side elevation, and the fuse cutout being illustrated inits operative condition for carrying line current therethrough;

FIGS. 2 and 3, respectively, are side elevational and rear elevationalviews of the improved latch bracket, which is secured to the cutoutdoor;

FIGS. 4 and 5, respectively, illustrate side elevational and rearelevational views of the improved support link or terminal hinge, whichforms a part of the door assembly of the cutout;

FIGS. 6 and 7, respectively, illustrate side elevational and rearelevational views, of the assembly of the springbiased, fuse-linkflipper device mounted upon the terminal hinge;

FIGS. 8 and 9, respectively, illustrate front elevational and sideelevational views of the mounting bracket for the contact assembly;

FIGS. 10 and 11, respectively, illustrate front elevational and sideelevational views of the substantially elongated, box-like supportterminal for each contact assembly;

FIGS. 12 and 13, respectively, illustrate top plan and side elevationalviews of the improved contact for the upper contact assembly of the fusecutout;

FIGS. 14 and 15, respectively, illustrate top plan and 3,138,681Patented June 23, 1964 side elevational views of the back-up spring forthe upper contact assembly of the fuse cutout;

FIGS. 16 and 17, respectively, illustrate top plan and side elevationalviews of the improved lower contact assembly;

FIGS. 18 and 19, respectively, illustrate top plan and side elevationalviews of the back-up spring for the lower contact assembly;

FIG. 20 is a top plan view of the improved latch means for locking thefusible device into the upper contact assembly of the fuse cutout.

Referring to the drawings, and more particularly to FIG. 1 thereof, thereference numeral 1 generally designates an enclosed fuse cutout. Itwill be noted that generally the fuse cutout 1 includes an insulatinghousing 2, which may be formed of any desired insulating material, suchas porcelain.

The porcelain housing or box 2 comprises a rear wall 3, a top wall 4,and oppositely disposed side walls 5, 6, only the one side 5 beingshown. It will be noted, therefore, that the front and bottom of theporcelain box 2 are open. The rear wall 3 is provided with an inwardlyextending protuberance 7 forming with an integral flange 8 a transversebaflle intermediate the ends of the insulating casing 2. Theprotuberance 7, as shown, is provided with a cavity 11 opening to theouter side of rear wall 3 and adapted to receive one end of a mountingbracket 12 for supporting the casing 2, for example, from a cross-armhanger.

As shown in FIG. 1, the mounting bracket 12 may be apertured, as at 15,to provide better securement within a resilient cement 16 containedwithin the cavity 11 and may be of a type described in the hereinbeforementioned copending application. The cavity 11 may also be sanded duringfabrication of the fuse casing 2 for additional strength of securement.

Within insulating casing 2 there is provided upper and lower contactassemblies 17 and 18, respectively, secured within cavities 21, 22,respectively, provided in the inner surface of rear wall 3 of the casing2. The upper contact assembly 17 includes a forwardly projectingU-shaped contact strip 23 (FIGS. 12, 13) of any desired conductingmaterial, such, for example, as copper or the like, with a resilientU-shaped backing strip 24, shown more clearly in FIGS. 14 and 15 of thedrawings. Preferably, the backing strip 24 is formed from a suitableresilient material, such as Phosphor bronze.

The intermediate portions of each leg of the U-shaped contact 23converge as at 25, 25 and the end portions flare outwardly of the basicU-shape as at 26, 26 to receive and seat the upper end of a fuse element33 as hereinafter described. The flared portions 26 are canted outwardlyand downwardly with respect to a direction parallel to the basic planeof the strip so as to form a seat for the fuse tube perpendicular to thefirst described seating direction.

The resilient backer 24 includes intermediate converging leg portions27, 27 for mating with the curved portions 25, 25 of the U-shapedcontacts 23, and flared end portions 28, 28 for mating with flared orcanted end portions 26, 26 of contacts 23.

The lower contact assembly 18 includes a U-shaped contact strip 31 and aresilient U-shaped backing strip 32, the latter being formed from aresilient metallic material,

such Phosphor bronze. The intermediate portions of the contact legscoverge at 34 andthe end portions diverge at 35 to form a sloped surfacesuitable for engaging and stopping the movable contacts to behereinafter described. The intermediate and outer portions 38 of thecontact backer 32 are curved to respectively mate with the intermediateand outer portions 34, 35 of the contact strip 31. As shown in FIG. 10,the support terminal 38 has a pair of apertures 42 for receiving studs43 anchoring the stationary contacts 23 and backer 24 to the end ofsupport 38.

The contact and backing strips of both the contact assemblies 17, 18 aremounted in position between one side 37 of the an elongated box-shapedsupport terminal 38 (FIG. 11) and the upper side 39 (FIG. 9) of anangleshaped support bracket 40, a pair of rivets 41 being employed forthe connection.

It will be observed that contact strip 23 has a downwardly extending endportion 44 (FIG. 13), which is disposed within box-shaped supportterminal 38, as more clearly shown in FIG. 1 of the drawings. Lowercontact strip 34 (FIG. 17) likewise has a depending portion 45, which issimilarly positioned. A pair of terminal screws 46 are threaded intothreaded apertures 47 (FIG. of each support terminal 38 and havecontacting shoe clamps 48 rotatably secured thereto at the inner endsthereof.

As aresult of the foregoing construction the line conductor and also theload conductor, not shown, may be threaded intothe side lead openings 49of casing 2 and forced under pressureby the contacting shoe clamps 48directly against the curved depending receptive portions 44, 45 ofcontact strips 23, 31, respectively. As a result, no unnecessary jointsare provided in the current path extending through the fuse cutout 1.

It will be noted that the angled support brackets 40 have an angledportion 50, which is cemented into the cavities 21, 22 of the casing 2.Any suitable cement, such as high-strength mineral lead cement 51 may beemployed.

With reference to FIG. 1, it will benoted that the porcelain fusehousing 2 is provided with threaded metallic pivot pins 53 extendingthrough opposite sides 5, 6 of the housing 2 and retained bycooperatinginsulating nuts (not shown). The pins 53, only one of whichis shown, form inwardly extending trunnions to removably pivotallysupport a fuse-holder door, generally designated by the referencenumeral 57.

Preferably the fuse-holder door 57 is formed of a suitable insulatingmaterial, such, for example, as porcelain, a synthetic resin, or thelike. The molded door 57 is provided with an apertured handle 58, whichmay be manipulated by a switch stick at a distance, or by hand forthelower'voltages. Theopening 59 in the handle 58 may be grasped by thehand of the lineman, but preferably for reasons of safety, switch stickoperation is desirable with the prong of the switch stick insertedwithin the opening 59 to effect closing and opening rotative motion ofthe fuse-holder door 57 about the pivot pins 53, as hereinafter morefully described.

Fuse-holder door 57 comprises a door panel 60 having a rearwardlyextending integral, apertured mounting projection 61. In addition, door57 has an intermediately disposed recess 63 for the accommodation of asponge rubber, washer-shape barrier member 64, and rivets 65 molded withthe door. Also fuse-holder door 57 has a transverse integral liange 66with an arcuate cutout portion, not shown, for accommodating a tubularfuse holder, generally designated by the reference numeral 68. The lowerportion of the molded door 57 is provided with a pair of trunnionreceiving flared notched 71 for receiving thepivot pin 53 on casing 2.The top of the door 57 is provided with a top, inwardly extending flangeportion 73.

The tubularfuse holder 68 comprises a top knurled contact cap 74, whichis threaded into a fuse ferrule 75, the

4 latter, in turn, being threaded upon the upper threaded end of a fusetube 76 and fixedly cemented thereto.

It will be noted that the contact cap nut 74 of fusible device 33 istapered from the base upwardly toward the top to fit in mating relationwith the previously described flared portion 26 of contacts 23. Inaddition, the cap has a cylindrical recess 77, which is engaged by thelatching portion 67 of spring latch 72 (FIG. 20). The spring latch 72has a coiled base portion terminating in ears 52 for attaching the latchto the support 38 by way of studs 43. The coiled wire spring is betterable to absorb the greater reaction due to jet forces duringinterruption. The coiled spring can better absorb deflection due tothese forces than can the flat spring of the copending application.

The mounting aperture 78 of mounting projection 61 has a shoulderportion 81, which limits the downward movement of fuse ferrule 75 whentubular fuse holder 68 is inserted into mounting aperture 78.

As well known by those skilled in the art, a buttontype fuse-linkassembly, generally designated by the reference numeral 82, is insertedinto the top of tubular fuse holder 68 following removal of knurledcontact cap 74. The buttonhead of the link assembly is clamped betweenthe bottom of the contact cap 74 and a threaded plug, not shown,threaded interiorly within fuse ferrule 75. The fuse link may be of thetype described in United States Patent 2,343,723, issued March 7, 1944,to James M. Wallace and assigned to the same assignee as the presentapplication.

The lower cable or tail 83 of the fuse-link assembly 82 extends throughthe lower open end of the bore provided within fuse tube 76 and isclamped between a freely rotatable washer 84 of a terminal clamp 85 andthe knurled side 86 (FIG. 5) of a pivotally mounted support link, ordoor hinge 87, shown more clearly in FIGS. 4 and 5 of the drawings. Inthe intact, or unblown condition of the fuse link 82, as illustrated inFIG. 1, a toggle means 88 is maintained in its set or unbroken position.However, when fuse link 82 fuses upon overload or faultcurrentconditions, the cable 83 is released, and the toggle means 88 breaks, orcollapses, to permit lowering andoutward movement of the fuse-folderdoor 57 and consequent unlatching of contact cap 74 from latching spring72. The entire fuse-holder door 57 then drops downwardly to the dropoutindicating position shown by dot-dash lines in FIG. 1.

Preferably, the fuse tube 76 is composite in construction having aninner gas-evolving liner of fiber, or like material, and an outersurrounding casing of insulating material preferably glass reinforcedepoxy. By using a strong outer layer, greater bursting strength isachieved and a thinner outer wall is permitted, thus allowing a thickerlayer of fiber. The thicker fiber provides a greater ability towithstand erosion due to arcing. The evolution of the gas from the fiberliner during the drawing of the are within the fuse-tube bore willassist in arc extinction, the evolved gas being expelled downwardlythrough the lower open end of the fuse tube 76 with expulsive action.This expulsive action will, of course, assist in the ejection of thelower remnant of the fuse link out of the fuse tube.

With reference to FIGS. 2 and 3, it will be noted that the rivets 65,molded with the door 57, are employed to secure fixedly in place a latchbracket, or catch 93. The rivets 65 extend through holes 94 of latchbracket 93 and have their inner ends swaged, or peened over to rig idlymount the latch bracket 93 on the door 57. Preferably, a resilientrubber pad 95 of generally rectangular configuration is disposed betweenthe inner side of the door panel 60 at the bottom of a recess 96, andthe bight portion 97 of latch bracket 93 for minimizing shock imposedupon the molded door 57 during operation of the cutout. The pad 95 is,of course, provided with apertures to accommodate the pair of rivets 65.

As shown in FIGS. 2 and 3, the legs 98 of latch bracket 93 have threethreaded holes 99 provided in the sides 98 of the latch bracket 93. Theupper two holes 99 receive the inner ends of pivot screws 102 (FIG. 1),the shank portions of which pass with clearance through pivot holes 103(FIG. 4) of supporting link 87. The inner extremities of the two pivotscrews 102 extend into bored openings, or recesses provided in the sidewalls of fuse tube 76. These recesses, not shown, do not, however,extend to the inner surface of the bore extending through fuse tube 76.Thus, the inner ends of the pivot screws 102 serve to fixedly attach thefuse holder 68, including the fuse tube 76, to the door 57. Byunscrewing the pivot screws 102, however, the supporting link 87 mayreadily be removed from the latch bracket 93, or door 57, and the freedfuse tube 76 may be removed from door 57 by upward withdrawal movementthrough mounting aperture 78 of projection 61. When desired, a new fusetube 76 may be substituted in this manner for an old fuse tube 76. It isto be noted that the latch bracket 93 has been provided withconsiderable mass and increased strength by the addition of integralconnecting member 101 connecting the legs 98 and the bight portion 97.This structure provides strength to resist the greater reaction forcesencountered at the higher interrupter ratings.

The toggle means 88 comprises the fuse holder 68 as one leg of thetoggle, and the supporting link 87 as the other leg of the toggle. Asshown in FIGS. 1 and 4, the supporting link 87 has provided adjacent thelower end thereof a slot 104 opening to one edge of the link and havinga reentrant portion 105 at the inner end thereof for receiving the pivotpins 53 supported upon the side walls 5 and 6 of the casing 2. By theprovision of such a slot 104 in supporting link 87, it will be apparentthat the link 87 may be readily attached and detached with respect tosupporting pivots 53 by movement of the link 87 to cause entrance orexit of supporting pins 53 into slots 104. In the position of the partsshown in FIG. 1 of the drawings, it will be noted that slot 104 in thesupporting link 87 lines up with the notches 71 provided in oppositeside edges of door panel 60 to permit the link 87, when assembled withthe fuse holder 68 and door 57, to be engaged or disengaged with pivotpins 53. The notches 71 in the door panel 60 are, as shown, flaredoutwardly to facilitate easy entrance of pivot pins 53 into the notches71 and slots 104 in the supporting link 87.

The lower threaded hole 99, as shown in FIG. 2, accommodates aconverting screw 106, which passes with clearance through hole 107 (FIG.4) of link 87, and thereby adapts the fuse cutout 1 for non-dropoutoperation. Removal of this converting screw 106, which is mounted inplace at the factory, provides dropout operation, since the toggle means88 is then free to collapse. If the converting screw 106 is maintainedin position, as supplied from the factory, the supporting link 87 isrigid with latch bracket 93 and door 57, and the toggle means 88 isrendered inoperable.

With reference to FIGS. 6 and 7 of the drawings, it will be noted that aspring latch, generally designated by the reference numeral 108, ismounted at the lower end of the supporting link 87. This spring latch108, mounted upon the door-hinge assembly, permits only a correct andcontrolled force upon the fuse link and aids the fuse cutout 1 inclearing faults. It also serves as a fuse-link flipper, indicating ablown fuse when the fuse cutout 1 is adjusted for non-dropout operation.

The spring latch 108, as shown in FIGS. 6 and 7, includes an elongatedmetallic sleeve 109 threaded upon the bight portion of a biasing spring110 comprising two torsion-spring sections 111. The ends 112 of thetorsion springs 111 bear upon the under side of the bight portion 86 ofsupporting link 87. The elongated metallic sleeve 109 is free to rollabout the bight portion of the biasing spring means 110.

As shown in FIG. 1, the spring-latch sleeve 109 not only exerts theproper pressure upon the fuse-link assembly 82, but also the metallicsleeve 109 latches behind the depending legs 98 of latch bracket 93preventing breaking, or collapse of the toggle means 88 until after thefuse link has blown and permitted downward releasing movement of thelatching sleeve 109.

With reference to FIG. 4, it will be noted that supporting link 87 has acontacting portion 116 with an arcuate cutout portion 117 foraccommodating the fuse tube 76 in the closed-circuit position of thedevice, as shown in FIG. 1. The contacting portion 116 has flared ends114 for mating engagement with portions 35 of the lower contact strip 34of lower contact assembly 18 with a wiping and pressural engagement. Theupper contact cap nut 74 likewise engages the contact plate legs 26, 26with pressural engagement. Thus, adequate contact pressure is providedin the latched closed position of the fusible device 1. This contactpressure tends to cause breaking or collapse of the toggle means 88,which is resisted by the fuse-link assembly maintaining the spring latchin its locking position, as shown in FIG. 1. The use of the U-shapedcontacts rather than the flat spring contacts of the copendingapplication provides firmer contact during passage of current whichprovides magnetic flux holding the contacts together to minimizeburning, and, further, the contacts as shown permit an upward motion ofthe door 57 during interruption without overstressing the stationarycontacts. The contact pressure provided between the resilient U-shapedlower contacts 31 and the movable contacts 116 on support link 87 in adirection perpendicular to the fuse tube serves to provide a forceurging the fuse tube 68 and support link 87 outwardly of the box 2 toassist in collapsing the previously described toggle mechanism when thefuse link 83 fuses. In the upper contacts, 23, the canted portions 26,26 permit the fuse tube 68 and contact 74 to drop downwardly during thetoggle breaking operation.

Referring to FIG. 6, it will be noted that a threaded bushing 118 isbrazed to the back side of supporting link 87 The threaded bushing 118threadedly receives the threaded shank portion of a terminal stud 119having an integrally formed outer wing nut 120. The stud 119 and wingnut 120 are formed from the same stock, the threads being rolled uponthe stock following positioning of the loose washer 84 thereon. Thethreads have an outer diameter greater than that of the hole through thewasher so the washer 84 is held captive. Also, the inner extremity ofthe terminal stud 119 is upset to render the terminal clamp 85 captiveupon the supporting link 87. The loose washer 84 prevents capstan actionbeing exerted upon the fuse-link cable 83 to prevent thereby theimposition of undue stress upon the relatively weak fuselink assembly82.

When the line conditions are such as to permit excessive current to flowthrough the cutout 1 by way of contact assemblies 17, 18 and fuse-linkassembly 82, this excessive current will cause fusing of the fusibleelement disposed within fuse tube 76 and associated with fuselinkassembly 82. The fusing of the fusible element will release thespring-biased latching device 108 causing it to rotate in acounter-clockwise direction about its pivot axis 121. The torsionsprings 110, encircling the sleeve 122, quickly force latching sleeve109 to effect withdrawal of the lower remnant of fuse-link assembly 82downwardly out of the lower open end of the fuse tube 76. Arclengthening is thereby augmented, and an indication of a blown fusecondition is obtained. Simultaneously with the withdrawing motion of thefuse-link flipper 108, there occurs unlatching of the cutout togglemechanism 88. Preferably, arc extinction occurs within fuse tube 76prior to breaking or collapse of toggle means 88 to prevent any arcingat the contacts. The force exerted by the lower back-up spring 32 actsto break the toggle means 88 and efi'ect counterclockwise rotation ofsupporting link 87 about its pivot axis 53, thus effecting outward anddropping movement of the fuse holder door 57 upon collapse of the togglemeans 88. This will release the latching means 67 at the top contactassembly and allow the tapered contact 74 to drop away from the cantedcontact 23. The fuse holder door 57 will swing in a counterclockwisedirection about the pivot pins 53 to the dot-dash open position of FIG.3.

The lineman will, of course,notice the. dropout position of the door, orif non-dropout operation is in effect, indication of the blown conditionof the fuse device 33 will be had by the lowered flipper device 10%which serves as a semaphore. If dropout operation is in effect, thelineman will insert a prong of his switch stick within operating eye 124(FIG. provided in link 87 and remove the fuse holder door 57 from thepivot pins 53. If non-dropout operation is in effect, the lineman mustfirst open the door 57 forcibly by pulling onthe prong of the switchstick inserted within door opening 59.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention, andthat it is intended by the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of the invention.

We claim as our invention:

1. A dropout fuse cutout, comprising: an insulating housing having pivotmeans disposed thereon, spaced upper and lower line contacts mounted onsaid housing, the upper one of said contacts comprising a pair ofresilient spaced opposing finger means extending in a first directionlaterally of a direction through said line contacts and each having aninner surface diverging with respect to the other in a direction towardthe other line contact; a fuse holder having a contact at its upper end;means including a collapsible linkage pivotally mounted on said pivotmeans and connected to said fuse holder; fuse link means connecting saidfuse holder contact to the lower one of said line contacts andreleasably holding said linkage in a non-collapsed position; saidlinkage being actuable to pivot said fuse holder contact in a directionopposite to said first direction into engagement with and between saiddiverging portions of said finger means; latch means engageable with thetop of said fuse holder contact to provide a force substantially axiallyof said fuse holder to releasably maintain the fuse holder contact inengagement with and between said finger means; said linkage beingcollapsible upon fusing of the fuse link to effect movement of said fuseholder in the direction of said inner surface divergence to effectdisengagement of the fuse holder contact from the finger portions of theline contact and the latch means.

2. A dropout fuse cutout, comprising: an insulating housing having pivotmeans disposed thereon, spaced upper and lower line contacts mounted onsaid housing, the upper one of said contacts comprising a pair ofresilient spaced opposing finger means extending in a firstdirectionlaterally of a direction through said line contacts and eachhaving an inner surface diverging with respect to the other in adirection toward the lower line contact; a fuse holder having a contactat its upper end; means including a collapsible linkage pivotallymounted on said pivot means and connected to said fuse holder; fuse linkmeans connecting said fuse holder contact to the lower one of said linecontacts and releasably holding said linkage in a non-collapsedposition; said linkage being actuable topivot said fuse holder contactin a direction opposite to said first direction into engagement with andbetween said diverging surfaces of said finger means; a spring latchreleasably engaging the top of the fuse holder contact to retain thefuse holder contact in engagement with and between said fingers; saidlinkage being collapsible upon fusing of the fuse link to effectmovement of said fusekholder in the, direction ofv said inner f surfacedivergence to effect disengagement of the fuse holder contact from thefinger portions of the line contact and said latch.

3. A dropout fuse cutout, comprising: an insulating housing having pivotmeans disposed thereon, spaced upper and lower line contacts mounted onsaid housing, the upper one of said contacts comprising a pair ofresilient spaced opposing finger means extending in a directionsubstantially perpendicular to an imaginary line connecting the contactsand each finger having a surface diverging downwardly; a fuse holderhaving a contact at itsupper end; means including a collapsible linkagepiv-. otally mounted on said pivot means and connected .to said fuseholder; fuse link means connecting said fuse holder contact to the lowerone of. said line contacts and releasably holding said linkage in anon-collapsed position; said linkage being actuable to pivot said fuseholder contact in a non-axial direction into engagement with and betweensaid diverging portions of said finger means; said fuse holder contactbeing tapered in a direction axially 0f the fuse holder at the locus ofengagement with said fingers to provide quick disengagement when thelinkage collapses; latch means engageable with the top of said fuseholder contact to provide a force substantially axially of said fuseholder to releasably maintain the fuse holder contact in engagement withand between said fingers; said linkage being collapsible upon fusing ofthe fuse link to effect movement of said fuse holder to effectdisengagement of the fuse holder contact from the finger portions of theline contact and the latch means.

4. A dropout fuse cutout, comprising: an insulating housing having pivotmeans disposed thereon, spaced upper and lower line contacts mounted onsaid housing, the upper one of said contacts comprising a pair ofresilient spaced opposing finger means extending in a first directionlaterally of a direction through said line contacts and each having aninner surface diverging with respect to the other in a direction towardthe other line contact;.a fuse holder having a contact at itsupper end;means including a collapsible linkage pivotally mounted on said pivotmeans and connected to said fuse holder; fuse link means connecting saidfuse holder contact to the lower one of said line contacts andreleasably holding said linkage in a non-collapsed position, saidlinkage being. actuable to pivot said fuse holder contact in a directionopposite to said first direction into engagement with and between saiddiverging portions of said finger means; said contact having a taperedsurface engaging the said inner surface of each finger when the fuseholder contact is between the fingers, latch means engageable with thetop of said fuse holder contact to provide a force substantially axiallyof said fuse holder to releasably maintain the fuse holder contact inengagement with and between said fingers; said linkage being collapsibleupon fusing of the fuse link to effect movement of said fuse holderinthe direction of said inner surface divergence to effect disengagementof the fuse holder contact from the finger portions of the line contactand the latch means.

5. A dropout fuse cutout, comprising: an insulating housing having pivotmeans disposed thereon, spaced upper and lower line contacts mounted onsaid housing, each of said contacts comprising a pair of resilientspaced opposing finger means extending in a first directionlaterally ofa direction through said line contacts, each finger having an endportion diverging with respect to the other finger of the correspondingpair, each finger of the upper contact having an inner surface divergingwith re-, spect to the other in a direction toward the lower linecontact; a fuse holder having a contact at its upperend; means includinga collapsible linkage pivotally mounted on said pivot means andconnected to said fuse holder; fuse link means connectiong said fuseholder contact to the lower one of said line contacts and releasablyholding said linkage in a noncollapsed position, said linkage beingactuable to pivot said fuse holdef contact in .a.

direction opposite to said first direction into engagement with andbetween said diverging portions of said finger means; contact means onthe linkage resiliently engageable with the finger portions of the lowerof said line contacts when the linkage is in the non-collapsed conditionand when the fuse holder is engaged with said one line contact; saidanother resilient line contact providing a force against said linkagecarried contacts tending to assist collapse of said linkage when thelinkage is released; latch means engageable with the top of said fuseholder contact to provide a force substantially axially of said fuseholder to releasably maintain the fuse holder contact in engagement withand between said fingers; said linkage being collapsible upon fusing ofthe fuse link to effect movement of said fuse holder in the direction ofsaid inner surface divergence to effect disengagement of the fuse holdercontact with the finger portions of the line contact and the latchmeans.

References Cited in the file of this patent UNITED STATES PATENTS1,864,283 Steinmayer June 21, 1932 2,134,075 Dey Oct. 25, 1938 2,176,045Birkenmaier Oct. 7, 1939 2,199,908 Birkenmaier May 7, 1940 2,525,999Birkenmaier Oct. 17, 1950 2,636,954 Hellstern Apr. 28, 1953

1. A DROPOUT FUSE CUTOUT, COMPRISING: AN INSULATING HOUSING HAVING PIVOTMEANS DISPOSED THEREON, SPACED UPPER AND LOWER LINE CONTACTS MOUNTED ONSAID HOUSING, THE UPPER ONE OF SAID CONTACTS COMPRISING A PAIR OFRESILIENT SPACED OPPOSING FINGER MEANS EXTENDING IN A FIRST DIRECTIONLATERALLY OF A DIRECTION THROUGH SAID LINE CONTACTS AND EACH HAVING ANINNER SURFACE DIVERGING WITH RESPECT TO THE OTHER IN A DIRECTION TOWARDTHE OTHER LINE CONTACT; A FUSE HOLDER HAVING A CONTACT AT ITS UPPER END;MEANS INCLUDING A COLLAPSIBLE LINKAGE PIVOTALLY MOUNTED ON SAID PIVOTMEANS AND CONNECTED TO SAID FUSE HOLDER; FUSE LINK MEANS CONNECTING SAIDFUSE HOLDER CONTACT TO THE LOWER ONE OF SAID LINE CONTACTS ANDRELEASABLY HOLDING SAID LINKAGE IN A NON-COLLAPSED POSITION; SAIDLINKAGE BEING ACTUABLE TO PIVOT SAID FUSE HOLDER CONTACT IN A DIRECTIONOPPOSITE TO SAID FIRST DIRECTION INTO ENGAGEMENT WITH AND BETWEEN SAIDDIVERGING PORTIONS OF SAID FINGER MEANS; LATCH MEANS ENGAGEABLE WITH THETOP OF SAID FUSE HOLDER CONTACT TO PROVIDE A FORCE SUBSTANTIALLY AXIALLYOF SAID FUSE HOLDER TO RELEASABLY MAINTAIN THE FUSE HOLDER CONTACT INENGAGEMENT WITH AND BETWEEN SAID FINGER MEANS; SAID LINKAGE BEINGCOLLAPSIBLE UPON FUSING OF THE FUSE LINK TO EFFECT MOVEMENT OF SAID FUSEHOLDER IN THE DIRECTION OF SAID INNER SURFACE DIVERGENCE TO EFFECTDISENGAGEMENT OF THE FUSE HOLDER CONTACT FROM THE FINGER PORTIONS OF THELINE CONTACT AND THE LATCH MEANS.